For several years a tritium-labeling facility has been in operation at the Lawrence Berkeley Laboratory (LBL). It has been used to prepare high specific activity 3H labeled compounds to further the biologically oriented research of many laboratories. The facility is also used for research into the mechanisms by which tritium atoms are incorporated into bio-organic compounds. The facility is equipped to handle safely up to 10,000 curies of T2, making it unique in the nation. It is also equipped to achieve tritium labeling by several techniques, such as exchange, catalytic hydrogenation, and microwave discharges in T2. During the past 2-3 years, requests to use the facility have come from researchers all over the nation; these requests have outstripped the capacities of the LBL personnel and equipment. It is apparent that an ability to meet this rising demand for high specific activity tritiated compounds would be a considerable service to the nation's research in biology and biochemistry. It is therfore proposed that the facility be expended to make it a national facility for tritium research and for tritium-labeling services. The proposed facility would enable researchers to come from all over the nation, to take part in tritium research, to consult with tritium-labeling experts regarding the best method for tritium incorporation into biologically valuable compounds, to carry out the labeling under close supervision, and to purify the labeled compound to a degree suitable for research in the home laboratory. This effort would be conducted simultaneously with a research program that will continuously add to our knowledge of tritiation reaction mechanisms.